This is a Rectify Series drop-in speaker system for Stewart/Bowser VO-1000 locomotives. The speaker uses double-sided mounting tape or a touch of adhesive to mount and requires removal of the factory PCB and use of a Nix Trainz Decoder Buddy motherboard (or similar) or a hardwire decoder installation.
 
The speaker comes fully assembled and tested.
 
Dimensions are: 9mmH x 17mmW x 32mmL
 
VIDEO: https://youtu.be/tKJLC6EOfws